Zhaozhou Congshen, who is said to have lived to a hundred and twenty, taught in plain words. Asked about the meaning of Bodhidharma’s coming from the west, he answered: the cypress tree in the garden. His reply “Wu” to the question of a dog’s buddha-nature became the most famous kōan of all.
Zhaozhou
A ninth-century Chinese Chan master famed for brief, ordinary replies that became classic kōans.
Also: Joshu, Chao-chou